18 INTRODUCTION. 



that these nearly allied members of the same genus are 

 specifically distinct animals. The jackal, although he 

 has been found diffused over most parts of the old 

 world ^, yet he has never become naturalized to the 

 new; and from some attempts to transplant him, it ap- 

 pears that he was not formed to live, like the dog, as 

 an exotic. It may be further observed, that, among the 

 efforts made to reclaim both the Asiatic and African 

 breeds, there are not sufficient authorities to prove that 

 any have succeeded, except in one small variety called 

 the adive, and with him but imperfectly ; and although 

 the number and direction of the bones of his skeleton 

 are similar to those of the dog, yet there is a very con- 

 siderable disproportion between the length of the fore 

 and hinder extremities, which gives to his whole exte- 

 rior an appearance unlike to that of any race of dogs 

 at present known. These considerations would seem 

 to disprove the origin of the dog from the jackal; and 

 if the account is true (but which I much doubt), that 

 the female jackal gestates only four weeks, the subject 

 receives a decisive confirmation. 



Between the Hyaena and the dog the lines of distinc- 

 tion are so apparent, that no relationship has ever been 

 attempted to be proved between them. 



I have yet to examine upon what authority the opi- 

 nion rests, that derives the dog from an accidental mix- 

 ture of such nearly allied animals, as, by engendering, 

 can produce fruitful uff«priug. The zoologists of the 

 last century were led to regard, as a criterion of spe- 



^ Copiosissimum in uuiverso oriente animal. — Pallas. It may be 

 also observed, that, were the dog a descendant from the jackal, it 

 is more than probable mixed breeds would be prevalent; but this 

 is never the case. 



